Reptiles : General Characters and Examples

 

Defination 

• Reptiles are class of  vertebrates that are cold blooded and skin is covered by scales and their young one are hatched from their egg. 

General Characters 

• They do locomotion through creeping or crawling. 

• They are mostly terrestrial but some are also found in water 

• Their skin is dry and cornified and covered by epidermal scales or scutes.

• They do not have external ear opening and A tympanum represent the ear. 

• They have two pairs of limb if present.

• Reptiles are Poiklothermal or cold blooded.

• Heart is three chambered except the Crocodiles have four chambered heart. ❤️

• Snake and Lizard shed their scale as skin cast.

• Saxes are seprate. Fertilization is internal. 

• They are oviparous and development is direct.

Examples of Reptiles 

1. Chelone

• It is commonly called as Turtle.

• Body is covered by a outer hard shell made up of Keratin. Upper part of shell is called carapace and lower part of shell is plastron.

• They have paddle like flippers on fore limbs.

• They have four limb with five digits hence called Pentadactyle.

• They are tooth less and omnivorous reptile.

• They have trochlear system on jaw adductor muscles.

• They use their shell to store lactic acid and to buffer the acidity.

• They are oviparous with internal fertilisation.

• They are uricotelic due to release of uric acid as excretory waste.

• They have no external ear and their skull is mono condaylic skull.

• Some species of chelone are endangered.

2. Python

• It is commonly called as Ajgar.

• It is large , non poisonous snake with triangular head with sharp teeth and prehensile tail.

• Head  has  heat sensitive pits  on their snouts and vertical pupils.

• Skin is flexible with smooth scales.

• They have a primitive lungs with reptiles ancestor characters.

• They are strike  predator and kill the prey  through its construction.

• Female Python lay leathery eggs and coiled around them to keep their warm.
• Python can live more than 20 years. 

• Python secrete large amount of mucus with trace amount of venom during the swallowing of prey. 

3. Testudo

• It is commonly called as Tortoise.

• It has dome and oval l shape shell with horny scales.

• When, it withdraw it's head into shell than it neck look like S shape.

• Carapace is convex with no nuchal plate whereas plastron in Concave.

• There are large yellow stars on both marginal and central scales.

• Feet are  for walking on land. Phalanges are reduced into two in each digit.

• Testudo can live upto 200 or more years. It can hibernate in cold water.

• It is diurnal, herbivores but it can feed insect and worms.

4.Hemidactylus

• It is commonly called as Wall lizard.

• Body is covered by scaly integuments. Scales are minute and smooth .

• Head is broad and flat. Eyelids are fused over the eyes. Ear opening is vertical.

• Tongue is short,  sticky and protrusible.

• Digits are clawed and dilated with row of ridged lamellae on lower surface for movement of ceiling or smooth surface. 

• Tail is long and can break off at any un ossified  part of caudal vertebrae. This is called Autotomy.

• Tail has great power of regeneration. Supra temporal arch is present.

• Parietal organs are present. Vertebrae are amphicoelous.

• They are oviparous and lay eggs.

5. Calotes

• It is commonly called as Garden lizard and found in open field or hedge.

• Body is covered by imbricate  epidermal horny scales. are minute and smooth .

• A crest of sharp spines is present on dorsal surface of neck and back.

• Body is divided into head, trunk and tail. Mouth is anteriorly located on head.

• Cloacal aperture is located at ventral surface of root of tail.

• Tail is long and cylindrical and does not has power of regeneration.

• It has capability to change the body color with respect to surrounding , called camouflage.

• There are 9 or 10 pairs of upper and lower labials.

6. Alligator 🐊

 

• Body is covered by  epidermal horny scales.

• Head is short and broad. Snout is also broad and rounded.

• Limbs are Pentadactyle with five finger and four toes. Fingers and toes are webbed.

• Tail is laterally compressed.

• Mandibular symphysis is short and extended upto level of fourth and fifth tooth. 

• There are 17 to 20 teeth in upper jaws and 18 to 20 teeth in lower jaws.

• Dorsal shield is formed by the 6 to 8 longitudinal series of Bony scutes.

• The neck is protected by the two pairs of large scutes.

7. Crocodilus

• It is commonly called as Crocodile.

• Head is triangular and rough at the top. Snout is short rathar than broad.

• Limbs are Pentadactyle with five finger and four toes. Fingers and toes are webbed.

• Tail is long and laterally compressed.

• Mandibular symphysis is short and extended upto level of fourth and fifth tooth. 

• There are 19 teeth in upper jaws and  lower jaws

• The nuchal scutes are six in number.

• Dorsal shield is formed by the four  to six row of larger  scutes. Out of these, central one is broader.

8. Bungarus 

• It is commonly called as Krait.

• Body is elongated and slender. The color of body is steel blue with cross bars or white speck on dorsal side and white in under side. 

• Head is with normal shield and not differentiated from neck .

• Loreal is absent. Two post ocular and one pre ocular are present.

• Seven supra labial are present . Third and fourth supra labial touches with eyes.

• It is nocturnal and carnivorous and feeds of rats and Lizards.

• Bungarus is poisonous and it's venom is neurotoxic.

• Bungarus is oviparous.

9. Vipera

• It is commonly called as Russell viper or Dabois.

• Body is elongated and slender. The color of body is pale brown  with three longitudinal series  of black  spots on dorsal side and yellowish white in under side. 

• Head is triangular and  covered with small imbricate scale on upper surface.

• The eye 👀 are with golden iris and with elliptical pupils.

• Ten to thirteen supra labial are present .  Fourth supra labial is largest and does not   touch with eyes.

• It is nocturnal and carnivorous and feeds of rats and Lizards.

• Viper is poisonous and it's venom is Haemotoxic.

• Viper is Viviparous.

10. Naja

• It is commonly called as Ki ng Cobra.

• Neck is dilatable and cervical ribs are elongated. The expansion of neck and cervical ribs forms hood.

• Head is with normal shield and not differentiated from neck .

• The upper part of hood has a Binocoellate mark. This mark is called as spectacles. 

• Third  supra labial is large and  touches with eyes and nasal.

• It is nocturnal and carnivorous and feeds of rats and Lizards.

• Cobra is poisonous and it's venom is neurotoxic.

• Eyes are very small with rounded pupils.

• Loreal is absent. Frontal shield is truncated.

• Three post ocular scales are present.

11. Chameleon

• It is commonly called as tree lizard.

• It has long sticky  tongue used to catch the prey. 

• It has movable eye which can move independently at 360 degree.

• Chameleon has color cells on skin called chromatophore to change the color.

• Toes are  modified as such way that these can grasp the  things.

• It has ability to change color for camouflage, communication and temprature regulation.

• The tail is prehensile to grasp the things.

• Generally they are oviparous but some give birth to young one.